The UN-backed government in Tripoli is close to pushing Islamic State fighters out of the coastal city of Sirte, considered one of the terror group's most important bases outside of Syria and Iraq. But with little sign of a return to stability across the country, Martin Kobler, the German career diplomat appointed to oversee the peace process in Libya, worries that the problem may simply be displaced elsewhere. He spoke to the FT's Heba Saleh about Libya’s wide-ranging problems during a recent visit to Cairo.